Electric call



(No ModeL) v 2 Sheets-Sheet 1.

D. H. RICE.

ELECTRIC GALLL No. 425,630. Patented Apr. 15, 1890.

lllllllllll A C) W I Lil-J UNITED STATES PATENT O IcE.

DAVID HALLRIOE, OF-LOVYELL, MASSACHUSETTS, ASSIGNOR TO THE CURRIER TELEPHONE BELL COMPANY, OF MASSACHUSETTS.

ELECTRIC CALL.

SPECIFICATION forming part of Letters Patent No. 425,630, dated April 15, 1890.

' Application filed February 13, 1882. Serial No. 52,586. (No model.)

To to whom it may concern.-

Be it known that 1, DAVID HALL Rim, of

Lowell, in the county of Middlesex and State of Massachusetts, have invented a new and usefullmprovementin Electric Calls, of which the following is a specification.

My invention relates to that class of electric calls patented to Jacob B. Currier, August 30 and December 20, 1881, in Patents No. 246,374 and No. 251,097 5 and it consists, first, in providing the vibrating caller with a novel makeand break connection with the electrical circuit, as hereinafter described; secondly, in organizing a series of such callers into a calling-machine by placing them upon acommon base and providing it with the necessary circuitconnections attached thereto, and keyboards to put either caller of the series into circuit, as desired; third, in providing said calling-machine with two or more sets of keyboards having duplicate keys connected to the same vibrating circuit-breakers; fourth, in incorporating into said calling-machine in connection with each key-board thereof a selfadjusting rheostat to equalize the resistance of the several circuits leading to the keyboards and enable the calls upon two or more circuits to be made at the same time by the same calling-machine; fifth, in connecting said self adjusting rheostat with a switchboard and two or more circuits of said Ourrier bells leading thereto, thereby enabling one rheostat to supply the place of a number which must otherwise be used; sixth, in providing the vibrating circuit-breaker and its tangent screw with an adjusting arrangement, whereby it may be adjusted with relation to its magnet, substantially as hereinafter described.

In the drawings, Figure 1 represents the improved callingmachine, its key boards, self-adjusting rheostats, switch board, and three circuits connected therewith and pro: vided with sets of the Currier bells. Fig. 2 shows a side elevation of one of the keys of the key-board. Fig. 3 is a front view of my improvements for adjusting the circuitbreaker and its connected mechanisms, and it also shows my improved contact mechanism for making and breaking the circuit. Fig. 4

is a side view of the same, showing the supporting-post of the contact-screw, partly in section, to display its method of insulation.

G Gr is the ground of all the circuits. L is the line leading to the caller. A is the baseboard of the caller. To its edge is secured the part of the line L extending along its side, as shown. Upon the base A are mounted a series of automatic circuit breakers 1), equal in number to the greatest number of bells upon any one of the circuits. These circuitbreakers operate substantially as shown in my application for Letters Patent thereon, Serial No. 45,955, filed November 16, 1881, but are modified, as hereinafter described. From the respective circuit-breakers shortlines connect them to the series of keys K, K K and K which are attached to the base A. These keys serve to connect the respective circuit-breakers with the line-wire L when desired.

Upon the base-board Ais secured an automatic rheostat R of the constructionand-operation described in the application for a patent of J acobB. Currier, filed December 15,1881, Serial No. 47,978. The line L leads to this rheostat and is secured to the base A. From this rheostat the circuit 0 leads outward to the subscribers stations, two of which S and S are shown upon the circuit provided with the Currier bells. The keys K K &c., are provided with screw-cups V at their bases, (see Fig. 2,) to which are connected a series of line-wires L, L L and L leading to the corresponding keys of the separate key-board D. A common line L for all these keys leads to another of said automatic rheostats R From this a short line leads to the switchboard E. This switch-board is of well-known construction, and is shown and described in my application for a patent filed October 15, 1881, Serial No. 43,84t-6. From this switchboard in the usual manner, as shown, lead the circuits 0 and O to the subscribers stations S, S S and S, each of which is provided with a bell of the Currier pattern.

It is of course understood that the caller, the key-board, the rheostats, and the switchboard are located at the central office, and that the circuits are at any distance apart and of any desired length.

B is the electric battery. The bells as they are used in this arrangement on the different circuits are so set at all the stations S. as to vibrate in the same time, and at all stations S and S respectively, in like manner. The vibrating circuit-breakers of the caller are set, respectively, to ring the bells at the different stations-that is, K rings S, K rings S K rings S and K rings 8. Now, let it be desired with this single caller to ring either two bells at different numbered stations on difierent circuits or at the same numbered stations on different circuits by two different operators in the central office at the same time. This is known to be frequently required in large telephone-ofiices, and is indeed indispensable to their business success.

The Currier automatic rheostat, as iswell known and demonstrated by itsdaily use, allows only the amount of electric current for which it is set or'gaged per bell to goto line 1 and then automatically interposes resistance cess of electric current tending to flow over 6' beyond what is needed is automatically stopped by the rheostat and turned back to supply circuit C, and each circuit gets suiiicient to ring any bells on each at the same time,and only the excess of battery-power,

' guit,the same as for circuit 0 if any, is acted upon by the rheostats. If circuit C be switched in instead of C the rheostat R will at once regulate the amount of electric current per bell going ov-erthe cir- By my arrangement, therefore, of key-boards, rheostats, and circuits I am able to. ring any bell on one circuit at the same time as any one on another, and by one or more operators in different places at the same time. I am also able to employ the excess of battery-power above what is needed for any particular circuit to run as many additional circuits as may be required up to the capacity of the battery without waste or loss of the same, which would not be possible with an ordinary rheostat. For instance, suppose an ordinar 1 rheostat is used to prevent an undue excess of battery-power from interfering with the proper operation of the bells on line C. When the line C is connected with the battery, the resistance of the common rheostat in line 0 would send the electric current over line 0 and the bells on line 0' would fail to ring at the same time as those on line C". To avoid this difficulty and operate bells upon either one or two or three circuits at pleasure,as described, with common rheostats is impossible, because the rheostat upon circuit C to.

is necessary to operate the calls upon that,

circuit, and if the calls of any other circuit were attempted to be operated at the samea time by making the resistance of both circuits alike, the sum of the resistance of both circuits would be greater than the battery-,

The, H

power and neither would be operated.

separate key-board D is also an important,

improvement in connection with the caller, for it can be set at any distance therefrom and several of them may be attached to as many different tables at the central office and at any convenient distance from the caller. enablesone caller to sufiice for the largest exchange when a Currier automatic rheostat This is used with each key-board,because any-cir:

cuit can be switched on to any key-board at pleasure, as is now done, and the work of the central office thus apportioned among its operators.

By attaching all thecircuit-breakers Z) I) to a single base A and providing it with -attached lines L L, and keys, if desired, or

screwcups for one or more sets of lines L, L

L and L leading to one or more key-boards, I organize the separate circuit-breakers and their attachments into a single instrument.

capable of being immediately placed in con.- uection with the system of any telephone-exchange without trouble or delay which. would otherwise occur. This is of great advantage.

My improvements in the vibrating circuitbreaker of the caller are shown in detail in Figs. 3 and 4, and in general in Fig. 1.

Great trouble has heretofore been expe.

rienced in so constructingacircuitbreaker to be operated by the electric current going to line that it would be set in motion by aslight current sufiiciently to be certain to operate and at the same time preserve its synchronous vibration accuratelyenough to be cer: tain to set in, motion the vibrating striker sought to be operated at a distant station. One method of accomplishing this result has been shown in a former application I-have made, wherein the tangent screw forming the electrical contact for the circuit-breaker to make and break against was made the center about which the circuit-breaker moved during part of its stroke. It was found that whenever an auxiliary light spring was used to make the electrical contact being attached 3,

to the circuit-breaker, and was placed in the ordinary manner so as to press against the fixed contact-point, or when the. auxiliary light spring was attached ,to the fixed point and made to bear upon a contact attached to the circuit-breaker, the consequent tension which it gave to the circuit-breaker spring, when sufficient pressure was applied to make a good electrical contact, prevented the circuit-breaker from being put invibration. so i as to make and break the circuit by means of the electric current of normal power passing over it. The reason why the method of overcoming this difficulty last above mentioned accomplished it was that the contact-point was placed so near to the post holdingthe vibrator-spring that a large part of the spring between it and the armature was not put in tension by its pressure, and the electric current could consequently set the circuitbreaker in vibration. The tension which the contact-screw did exert upon the circuitbreaker, however, rendered its proper adj ustment a matter of extreme nicety, and in addition, since it must be on the opposite side of the circuit-breaker from its magnet, it caused the circuit-breaker to make the longest portion of its beat toward the magnet, thus compelling the use of a very powerful magnet, so as to enable it to be set at a sufficient distance from the circuit-breaker and start the latter in movement. It is to remedy these inconveniences and produce an improved result that my present improvementis devised.

In the drawings, Figs. 3, 4, and 1, m m is the magnet. n is the vibrating armature carrying the circuit-breaker. q is the tangent screw. 29 is the light auxiliary spring which forms the electrical contact to be made and broken by the circuit-breaker. The circuit is formed through screw q, upon the contactpoint of which the auxiliary spring p bears, forming the electrical contact; thence it leads through spring 1), thence through post 0, in which the circuit-breaker spring is fixed, thence from the metallic base of said post through magnet m to the key of the caller or key-board. The screw q is supported by a post '1', which is secured by insulating material to the metallic base of the post 0, as hereinafter described. The spring 19 is placed in such-a direction and so bears upon its contact-point of the screw (1 as to leave the spring of the circuit-breaker n substantially without tension at the same time it forms the chord of the are having the gripping-point of the post 0 upon the circuit-breaker springas a center and passing through the contactpoint of the screw q. only leaves the spring of the circuit-breaker n in the most favorable position to be set in operation by the first impulses of the electric current, but it also causes the spring 19 to instantaneously leave the contact-point of its screw (1 when the circuit-breaker '77, moves from its normal position of rest toward the magnet, while when the circuit-breaker moves from said position away from the magnet it is but very slightly opposed by the tension of the spring 1), owing to the surface of the latter sliding along upon its screw contact-point. It will thus be seen that while I insure the most favorable position of the circuit-breaker to be set in motion by faint electric currents, I also insure the best breaking of the circuit during the movement of the circuit-breaker in one direction and a make of the circuit during its movement in the other direction,

This construction not which does not perceptibly interfere with the synchronism of its vibration with any striker at a distant station which it is used to operate. The result is that the capacity of the circuit-breaker to allow a great variation in the electric current by which it and the bellstrikers are to be operated is attained, and any variation of current which will permit of the bell-strikers being operated will also set in operation automatically the vibrating circuit-breaker. It is upon these two qualities that my improvement dependst'. e., that the auxiliary spring 19, when given sufficiei1ttension to make a good electrical contact, shall leave the circuit-breaker spring substantially without tension, which would prevent itsbeing set in motion effectively by the electrical current, and at the same time the spring 19 shall so bear upon its contact-point as to allow the latter to slide upon its surface when the contact is made by the movement of the circuitbreaker in one direction and leave its surface when the circuit-breaker moves in the other direction. I am thus able to accomplish what I believe has not before been done, which is to make a practical circuit-breaker operated automatically by the electrical current to be broken with perfect synchronism of movement under all ,the variations of such current which occur in its practical daily use over metallic casting of the usual form, screwed to the base A by the screw it. To its upright arm the magnet is secured by the screw 20'. Upon this base is secured the swinging armt by the screw a upon which it is pivoted. A slot at its free end with the clamp-screw 1L3 allows it to be swung around the pivot-screw a and fastened in any desired position, which movement adjusts the circuit-breaker n to or from its magnet. In order to insulate the post 4', which carries the screw q, and atthe same time support the post upon the swinging arm 75, I adopt the following construction: Through the swinging arm t a hole is made, which receives a washer of vulcanite h, Fig. 4, shouldered as shown. Through the center of this washer 1; passes a screw 16, having a large metallic washer uFbet-ween its head and the vulcanite to give it a broad bearingsurface upon the latter. On top of the swinging arm tis placed another piece of vulcanite insulating material v and 011 top of this a metallic plate 25 which bears only upon the vulcanite beneath it. The vulcanite and plate t have each a hole through them large enough to receive the screw uf and allow the latter to pass freely up into the post 4 where the screw takes into a corresponding thread in a hole in the post. It

willbe seen that when the screw u is set up solidly the post 4" will be rigidly secured to the swinging arm 2? while being insulated It is obviously a great advantage from it.

IIS

to have the screw q thus supported and adjusted simultaneously with the vibrating circuit-breaker, because the latter can thus be adjusted with relation to its magnet without disturbing the adjustment of its attached spring 1) and the screw q.

Instead of having 1) in the form of an elastic spring and the screw q rigidly fixed, 1) may be made rigid and the screw q held against it by elastic pressure, if desired,

which can be accomplished by giving the proper elasticity to the vulcanite pieces '0' and 4: or in any other suitable manner.

In order to cause the screw q to be carried forward accurately against the spring 19 to form a contact and to secure it in position when properly adjusted, the post '1' is so made that a screw-thread is cut in one branch of its bifurcated end 4', while the other branch has a longitudinal slot out down to the passage for the screw q, as shown in Fig.

3, and a grip-screw w is carried through across this slot and above the screw q, as

shown. By setting up the screw to this branch of the bifurcated post is made to clamp the screw q and hold it firmly in any desired position without disturbing its adjustment against the spring 13.

What I claim as new and of my invention 1s-- 1. In combination with the base-board A,

twoor more attached circuitbreakers b, and

the attached circuit L, and connecting short circuits. leading from the circuit-breakers b to a series of keys, the whole being organized into a completed calling-m achine and adapted to sound different alarms uponan electrical circuit connected therewith, substantially as described.

2. In combination with the callingmachine A, organized substantially as described, the independent key-board D, connected to the circuit-breakers of such calling-machine, substantially as described.

3. In combination with a single circuitbreaker 12, two or moreseparate keys K in electrical connection therewith and two or more corresponding circuits L L in connection with said keys, respectively, substantially as described. i

4:. In combination with a single circuit breaker b, two independent keys K electrically connected therewith, two corresponding electrical circuits L L respectively in connection with said keys, and two rheostats R B, respectively connected with said circuits, substantially as described.

5. In combination with a single circuit breaker b, the key K electrically connected therewith, the circuit U, the rheostat R the switch E, and the electrical circuits 0 0 substantially as described.

6. In combination with the magnet m, the swinging arm tand circuit-breaker n, attached thereto, substantially as described.

7. In combination with the magnet m, the

armature n, suspended upon a support upon which it vibrates to and fro, the contactspring 1), attached to the armature and having its contact-surface lying approximately in the direction of the line of its vibratory movement, the contact point arranged to bear upon said surface of the contact-sprin g transversely to its line of movement to and fro during partof the same, and an electric circuit leading through said contact-point, contactspring, armature, and magnet, and grounded on each side of the same, substantially as described.

11. The combination of the magnet 772, its armature n, suspended upon a support in position to be vibrated by an electric current passing-through the magnet, the electric conductor L, connected to said armature and grounded, a vibrating alarm-striker on the latter circuit, arranged to respond to its magnet synchronously with armature 11, an electrical contact-point connected to ground by the electric conductor L, a source of electric energy upon the latter, and the spring 19, projecting from the armature it past said contactpoint in adirection parallel,or approximately so, to its plane of movement, whereby its contact-surface is adapted to reciprocate bodily to and fro upon said contact-point and to leave the same when the armature is vibrated, substantially as described.

12. The combination of the magnet m, its armature n, suspended upon a support in position to be vibrated by an electric current passing through the magnet, the electric conductor L connected to said armature and leading to ground, an electric contact-point connected to ground by the electric conductor L, a source of electric energy upon the latter,

and the spring 19, projecting from the armature n past said contact-point in a direction parallel, or approximately so, to its plane of movement, whereby its contact-surface is adapted to reciprocate bodily to and fro upon said contact-point and to leave the same when the armature is vibrated, substantially as described. i

DAVID HALL RICE.

Witnesses:

LEPINE 0. RICE, N. P. OCKINGTON 

